A team of researchers in Italy set out to find if there was any statistical correlation between behavioral problems in dogs and various factors such as size, age, sex, mounting behavior, where the dog sleeps, and where the dog came from (e.g., a shelter or acquired from another person).

Turns out, there is.

Their study focused on 335 dogs that were brought to a behavioral clinic in Northern Italy between 2013 and 2016. The team divided the dogs into two main groups based on what kind of behavioral problem they were diagnosed with. One group was designated as aggressive, and the other was designated as anxious.

Each dog was evaluated by a veterinary specialist using a basic history questionnaire that delved into all aspects of the dog’s behavior and medical history. Researchers then selected several variables from the questionnaire and analyzed them.

Among their findings:

Female dogs were mostly anxious and male dogs were mostly aggressive

Small and medium sized dogs were mainly anxious

All the dogs adopted from pet shops were anxious

This study backed up the findings of another recent study that found a strong negative correlation between body-size and unwanted behaviors: in both studies, smaller dogs had significantly more compulsive behaviors, mounting behavior, separation-related problems, urine marking, but, most importantly, dog-directed fear and nonsocial fear.

Intact males were distributed between both diagnostic groups almost equally

75% of dogs age 1 year or less were anxious

78% of dogs that slept on their owner’s bed were anxious

In terms of treating the behavior problems, aggressive dogs had a better prognosis.

The suggested treatment plan included a combination of four basic strategies: education and modification of the client’s behavior, changes to the patient’s environment, changes of the patient’s behavior, and pharmacological therapy. The behavioral protocols were kept simple so they could be easily integrated into the owner’s daily routine. This also served to clarify owner-animal communication.

Researchers found that dogs who were diagnosed with aggression responded better to the treatment plan than dogs diagnosed with anxiety.

The researchers suggest that one possible reason for that outcome is that aggression is clear and dependent on context, which means the context can often be controlled. Hence, treatment is more effective because it’s easier. Whereas anxiety is generalized and diffused, which means it tends to occur in contexts that are more difficult to control. Hence, treatment is less effective because it’s harder.

Sadly, the disparity in ease of treatment between aggression and anxiety spells more bad news for anxious dogs: The researchers report that owners of anxious dogs were more likely to consider surrendering their dogs for adoption.

This reflects the results of an earlier study finding that anxiety-related problems is one of the leading reasons people surrender dogs to shelters.